Electromechanical steering mechanisms usually have an electric motor as servomotor. Servomotors of this design are actuated by a control unit via a set of MOSFETs, wherein with three phase windings six MOSFETs are provided in total. Each MOSFET switches the assigned phase winding to the on-board vehicle power-supply voltage or the earth potential. This occurs at a high frequency so that the temporal average value acts as the effective voltage in the phase windings. For safety reasons it is known to separate the phase lines in the neutral point of the motor. Separation takes place in a motor control unit (MCU) which is controlled with appropriate information from an electronic control unit (ECU). Signal lines are used to transfer this information and measured signals, for example angle of rotation of the motor measured by a rotor position sensor (RPS), between MCU and ECU. Thereby a separate line is required for each signal direction. Each signal line requires at each end a contact for signal transmission. These contacts are, however, error-prone because of the applied low voltages.
Thus a need exists for a simple and cost effective solution for transmission of electrical signals, where two-sided communication can be realized with less contacts and wires.